JP6263844B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus.

  Recording using the ink jet recording method is performed by ejecting and flying ink droplets and depositing them on a recording medium such as paper. Due to recent advances in inkjet recording technology, inkjet recording apparatuses using an inkjet recording method are also being used in the field of high-definition image recording in which photography and offset printing have been used.

  In the ink jet recording apparatus, when moisture or other volatile components contained in the ejected ink evaporate, the viscosity of the ink increases (thickens). In recent inkjet recording, the amount of ejected ink droplets is a very small amount of several picoliters, the diameter of the nozzle ejecting ink is small, and the energy required for ejecting ink droplets in order to perform high-definition recording Is also getting smaller. Since the nozzle diameter is small and the ejection energy is small, the ink that has adhered to the nozzle and thickened cannot be excluded, and the nozzle is likely to be clogged, resulting in an ink ejection failure. Furthermore, fibers generated from a recording medium such as paper and cloth, paper dust, and surrounding dust may also adhere to the nozzle forming surface (nozzle plate surface), and similarly, normal ink ejection is hindered.

  In order to prevent or reduce the above-described ink thickening and ejection failure due to foreign matter adhering to the nozzle plate surface, an ink jet recording apparatus including a wiper mechanism (recovery mechanism) has been proposed. For example, Patent Document 1 describes an ink jet recording apparatus provided with a cleaning mechanism using a wiping blade. Patent Document 1 discloses a technique for arranging fine particles on the surface of the wiping blade so as to reduce the coefficient of friction between the wiping blade and the head (nozzle plate surface) and protect the nozzle plate surface. Further, Patent Document 2 includes an application unit that applies a treatment liquid to a recording head or a wiping member as an inkjet recording apparatus that can simultaneously achieve low cost, high weather resistance, high durability, and high reliability. An ink jet recording apparatus that performs wiping when necessary, such as when it is determined that the (nozzle plate surface) is dry, is described.

JP 2006-142804 A JP 2009-101630 A

  However, the method described in Patent Document 1 has a problem that the ink wiping property is poor. Specifically, the cleaning using a wiping blade has a problem that it cannot be removed when the ink adhered to the nozzle surface, the nozzle plate cover, or the wiping blade is thickened and dried. In contrast, the method described in Patent Document 2 has improved wiping properties, but has a problem that the liquid repellent film formed on the surface of the nozzle plate is deteriorated. Specifically, in the case of an ink jet recording apparatus that performs recording using an ink composition containing an inorganic pigment, the inorganic pigment interposed between the wiping member and the nozzle plate surface during cleaning (wiping) is the nozzle plate surface. It has a problem of acting on the liquid repellent film and damaging the liquid repellent film. An inorganic pigment is a component that can easily damage a liquid repellent film (such as a metal alkoxide molecular film having liquid repellency), as represented by carbon black and titanium dioxide. When the liquid repellent film is damaged, ink ejection becomes unstable, and the landing positions of ink droplets are disturbed.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples or forms.

  Application Example 1 An inkjet recording apparatus according to this application example includes a first discharge port array in which discharge ports of a plurality of nozzles that discharge an ink composition containing an inorganic pigment are arranged, and a color material other than the inorganic pigment. A second ejection port array in which ejection ports of a plurality of nozzles ejecting an ink composition are arranged; a nozzle plate having the first ejection port array and the second ejection port array; and a liquid repellent provided in the nozzle plate A film, a wiping member that absorbs an ink composition that wipes the surface of the nozzle plate, and a moving mechanism that varies a relative position of the nozzle plate and the wiping member. In a series of operations wiped by the wiping member, the second discharge port array is wiped in preference to the first discharge port array.

  According to this application example, the surface of the nozzle plate is wiped by the wiping member, thereby preventing or reducing ejection failure due to thickening of the ink composition or adhesion of foreign matter to the nozzle plate. Further, in the series of wiping operations in which the surface of the nozzle plate is wiped by the wiping member, the second discharge port array is wiped in preference to the first discharge port array. The state in which an inorganic pigment intervenes between the nozzle plate surface is reduced. When the first discharge port array is wiped, the inorganic pigment may be pressed against the nozzle plate surface by the wiping member and rubbed, so the nozzle plate surface may be damaged in the vicinity of the first discharge port array. Since the second discharge port array is wiped preferentially in a state where there is no or little inorganic pigment, damage to the nozzle plate surface is suppressed.

  Thus, according to this application example, the inorganic pigment that is discharged from the first discharge port array and adheres to the nozzle plate is not damaged on the entire surface of the nozzle plate while being spread on the second discharge port array. Or, the degree of damage can be reduced. As a result, since the deterioration of the liquid repellent film over the entire nozzle plate is suppressed, the discharge of the ink composition can be maintained in a more stable state.

  Application Example 2 In the inkjet recording apparatus according to the application example, the moving mechanism may change a relative position between the nozzle plate and the wiping member so that the second discharge port array is wiped preferentially. Features.

  According to this application example, in a series of wiping operations, a first ejection port array that ejects an ink composition containing an inorganic pigment and a second ejection port array that ejects an ink composition containing a color material other than the inorganic pigment. In accordance with the arrangement, the moving mechanism changes the relative position between the nozzle plate and the wiping member so that the second discharge port array is wiped preferentially. In other words, the second discharge port row is wiped preferentially by the moving mechanism regardless of the arrangement of the first discharge port row and the second discharge port row. For example, in order to be able to record a high-definition image at high speed, a plurality of first discharge port arrays are arranged at positions separated so as to sandwich a plurality of second discharge port arrays. Or, conversely, even if the first discharge port array is sandwiched between the second discharge port arrays, the relative position between the nozzle plate and the wiping member varies, giving priority to the second discharge port array. Wiping is performed so as to be wiped off. As a result, the same effect as in Application Example 1 can be obtained, and the ejection of the ink composition can be maintained in a more stable state.

  As described above, according to this application example, the arrangement of the nozzle outlets in the nozzle plate, that is, the arrangement of the nozzle arrays in the inkjet head, can be performed without regard to the order of wiping. Therefore, it is possible to provide an inkjet recording apparatus that can record a higher-definition image at a high speed and has higher ejection stability.

  Application Example 3 In the ink jet recording apparatus according to the application example described above, the relative position between the nozzle plate and the wiping member varies in a single direction, and the second ejection port array is preferentially provided in the nozzle plate. The first discharge port array and the second discharge port array are arranged so as to be wiped off.

  According to this application example, in the wiping operation in which the relative position between the nozzle plate and the wiping member varies in a single direction, the first discharge port array and the second discharge port are preferentially wiped off. And an exit line. Since the effect similar to the application example 1 can be acquired by simple wiping operation | movement, the structure of a moving mechanism can be simplified more. As a result, it is possible to provide an ink jet recording apparatus in which ejection of the ink composition is more stable with a more simplified configuration.

  Application Example 4 In the ink jet recording apparatus according to the application example, it is preferable that the second discharge port array is wiped first.

  As in this application example, in the series of wiping operations in which the surface of the nozzle plate is wiped by the wiping member, the second discharge port array is wiped first by making the second discharge port array wiped first. Since it is wiped in a state where no pigment is present, damage to the nozzle plate surface is suppressed.

  Thus, according to this application example, it is possible to reduce the degree of damage to the entire surface of the nozzle plate due to the inorganic pigment adhering to the nozzle plate. As a result, since the deterioration of the liquid repellent film over the entire nozzle plate is suppressed, the discharge of the ink composition can be maintained in a more stable state.

  Application Example 5 In the inkjet recording apparatus according to the application example described above, when the number of the first ejection port arrays is n, the number of the second ejection port arrays is m, and k = (n + m) when n + m is an even number. / 2, and when n + m is an odd number, when k = (n + m−1) / 2, the wiping member moves the first discharge port array from the first to the (n + m) th to the first discharge port array or the first In a series of operations for wiping the two discharge port arrays, the rate at which the second discharge port array is wiped in the range from the first to the kth, and the second discharge port array is wiped in the range from the k + 1th to the n + mth. It is characterized by being greater than the rate.

  According to this application example, in a series of wiping operations in which the surface of the nozzle plate is wiped by the wiping member, the rate at which the second discharge port array is wiped in the first half (range from the first to the kth) of the wiping order is It is larger than the rate at which the second discharge port array is wiped in the latter half (range from k + 1 to n + m). In this way, the second discharge port array is wiped preferentially, so that the state in which the inorganic pigment is interposed between the wiping member and the nozzle plate surface is reduced in a series of wiping operations. As a result, the state in which the inorganic pigment discharged from the first discharge port array and attached to the nozzle plate damages the entire surface of the nozzle plate while spreading over the second discharge port array is reduced, and the degree of damage is reduced. can do.

  Application Example 6 In the ink jet recording apparatus according to the application example, it is preferable that an average particle diameter of the inorganic pigment is 20 nm or more and 200 nm or less.

  As in this application example, by setting the average particle diameter of the inorganic pigment contained in the ink composition to 20 nm or more and 200 nm or less, the ink composition constituting, for example, black ink or white ink can be stabilized as an ink jet recording apparatus. Can be discharged. Further, when the first discharge port array is wiped, an inorganic pigment having an average particle diameter of 20 nm or more and 200 nm is pressed against the nozzle plate surface by the wiping member and rubbed, so that the nozzle plate surface is near the first discharge port array. Although damage may occur, due to the effects described above, damage to the nozzle plate surface is suppressed even when such an inorganic pigment is used.

  Application Example 7 In the inkjet recording apparatus according to the application example described above, it is preferable that the needle ratio (maximum particle length / minimum width) of the inorganic pigment is 1.5 or more and 3.0 or less.

  As in this application example, by setting the needle-like ratio of the inorganic pigment contained in the ink composition to 1.5 or more and 3.0 or less, the image has excellent scratch resistance, album storage stability, oxidation gas resistance, and the like. An ink jet recording apparatus can be provided. Further, when the first discharge port array is wiped, an inorganic pigment having a needle-like ratio of 1.5 or more and 3.0 or less is pressed against the surface of the nozzle plate by the wiping member and rubbed. Although the nozzle plate surface may be damaged in the vicinity of the row, due to the above-described effects, damage to the nozzle plate surface is suppressed even when such an inorganic pigment is used.

Application Example 8 In the ink jet recording apparatus according to the application example, the ink composition containing an inorganic pigment, containing the concentration of the inorganic pigment is preferably 1.0 mass% or more.

As in this application example, the concentration of the inorganic pigment contained in the ink composition, 1.0 by at mass% or more, an ink jet recording apparatus capable of forming an image quality is excellent, such as contrast higher definition Can be provided. Further, when the first discharge port array is wiped, the surface of the nozzle plate may be damaged in the vicinity of the first discharge port array due to the inorganic pigment being pressed against the surface of the nozzle plate by the wiping member and rubbed. but the effect described above, the damage experienced by the nozzle plate surface even when containing such a 1.0 mass% or more inorganic pigments is suppressed.

1 is a perspective view showing an ink jet recording apparatus according to an embodiment. (A) Sectional drawing which shows a part of head, (b) The top view of the nozzle plate with which a head is provided. (A) The perspective view which shows a wiper unit, (b) The side view which shows the structure of a wiper unit, (c) The top view which shows the positional relationship of a wiper unit and a discharge port row | line | column. (A)-(c) The top view which looked at the nozzle plate which concerns on Embodiment 1-3 from the discharge outlet side. (A)-(c) The top view which looked at the example of the nozzle plate which concerns on Embodiment 4 from the discharge outlet side. (A), (b) The top view which looked at the example of the nozzle plate which concerns on a modification from the discharge outlet side.

  DESCRIPTION OF EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention. In the following drawings, the scale may be different from the actual scale for easy understanding.

FIG. 1 is a perspective view showing an ink jet recording apparatus 1 according to this embodiment.
First, the basic configuration of the inkjet recording apparatus 1 will be described.
<Inkjet recording apparatus>
An ink jet recording apparatus is an apparatus that records characters, drawings, images, and the like by ejecting ink (ink composition) with an ink jet recording head and attaching it to a recording medium. As a method of the ink jet recording head, a piezo method is used as a preferable example. The piezo method is a method in which a pressure corresponding to a recording information signal is applied to ink by a piezoelectric element (piezo element), and ink droplets are ejected and recorded.

  The method of the ink jet recording head is not limited to this, and other recording methods in which ink is ejected in the form of droplets to form dot groups on a recording medium may be used. For example, a strong electric field between a liquid ejection nozzle (hereinafter referred to as a nozzle) and an acceleration electrode placed in front of the nozzle causes ink to be ejected continuously from the nozzle in the form of droplets, and a recording information signal is given from the deflection electrode while the ink droplets fly. Recording method, or a method of ejecting ink droplets according to the recording information signal without deflecting (electrostatic suction method), applying pressure to the ink with a small pump, and mechanically vibrating the nozzle with a crystal resonator, etc. For example, a method of forcibly ejecting ink droplets, a method of heating and foaming ink with a microelectrode according to a recording information signal, and ejecting and recording ink droplets (thermal jet method) may be used.

FIG. 1 is a perspective view illustrating a configuration of an inkjet recording apparatus 1 as an example according to the embodiment. In FIG. 1, the ink jet recording apparatus 1 is installed on a substantially horizontal XY plane.
The ink jet recording apparatus 1 includes an ink jet recording head (hereinafter, recording head 20), a carriage 3, a carriage drive mechanism 4, a control board 5, an ink cartridge 6, a recording medium supply / discharge mechanism (not shown), a platen 8, a wiper unit 30, and the like. It has.
The carriage 3 has a recording head 20 and an ink cartridge 6 mounted thereon, and scans on the surface of the recording medium 10 by the carriage driving mechanism 4 (reciprocating operation in the X direction in FIG. 1) (approximately -Z in FIG. 1). Direction), ink (ink composition) is ejected and recording is performed.
The control board 5 performs drive control of the carriage drive mechanism 4 and the wiper unit 30, control of ink discharge, and control of supply and discharge of the recording medium 10.
The ink cartridge 6 is divided into a plurality of storage portions and stores a plurality of ink compositions described later.
The recording medium supply / discharge mechanism moves the recording medium 10 in a direction intersecting the scanning direction of the carriage 3 (Y direction in FIG. 1).
The platen 8 mounts the recording medium 10 and defines the interval between the recording head 20 and the recording medium 10.

<Recording head>
FIG. 2A is a cross-sectional view showing a part of the recording head 20.
The recording head 20 has a nozzle plate 22 provided with a plurality of nozzles 21 for discharging an ink composition, and the nozzle plate 22 has nozzle openings (discharge ports 23). A liquid repellent film 24 is formed on the surface of the nozzle plate 22.
The nozzle plate 22 is provided with a nozzle plate cover 25 that covers at least a part of the nozzle plate 22. The nozzle plate cover 25 serves to fix the nozzle chip 26 in the recording head 20 formed by a combination of a plurality of nozzle chips 26, or the recording medium 10 is lifted and the recording medium 10 comes into direct contact with the nozzle 21. It is provided for the role of preventing the situation. The nozzle plate cover 25 covers at least a part of the nozzle plate 22 so as to protrude from the nozzle plate 22 when viewed from the side. Since the ink composition may remain in the vicinity of the protruding portion and the ejection port 23, the ink composition is removed by a wiping member 31 (FIGS. 3A and 3B) provided in the wiper unit 30 described later.

FIG. 2B is a plan view of the nozzle plate 22 as viewed from the discharge port 23 side.
The nozzle plate 22 includes a first discharge port array 50 in which discharge ports 23 for discharging an ink composition containing an inorganic pigment are arranged, and discharge ports of a plurality of nozzles for discharging an ink composition containing a color material other than the inorganic pigment. And a second discharge port array 51 in which 23 are arranged. In the example shown in FIG. 2B, there are two first discharge port arrays 50 and seven second discharge port arrays 51 arranged in the Y direction.
Although description will be omitted, FIG. 2A shows a cross section taken along the line AA in FIG.
Further, in FIG. 2B and the drawings shown below, the rows of the discharge ports 23 painted black represent the first discharge port rows 50.

<Liquid repellent film>
The liquid repellent film 24 is not particularly limited as long as it is a liquid repellent film. The liquid repellent film 24 can be formed, for example, by forming a molecular film of a metal alkoxide having liquid repellency and then performing a drying process, an annealing process, or the like. The metal alkoxide molecular film may be any film as long as it has liquid repellency. However, the metal alkoxide monomolecular film having a long-chain polymer group containing fluorine (long-chain RF group), or a liquid-repellent group (for example, A monomolecular film of a metal acid salt having a long-chain polymer group containing fluorine). Although it does not specifically limit as a metal alkoxide, For example, silicon, titanium, aluminum, and zirconium are generally used as the metal seed | species. Examples of the long chain RF group include a perfluoroalkyl chain and a perfluoropolyether chain. Examples of the alkoxysilane having a long chain RF group include a silane coupling agent having a long chain RF group. Further, as the liquid repellent film 24, for example, an SCA (Silane Coupling Agent) film or a film described in Japanese Patent No. 4424954 can be used.

  The liquid repellent film 24 may be formed by forming a conductive film on the surface of the nozzle plate 22 and forming the conductive film on the conductive film. However, by first polymerizing a silicon material, a base film (PPSi (Plasma Polymerized Silicone) is formed. ) Film) may be formed and formed on this base film. Through this base film, the silicon material of the nozzle plate 22 and the liquid repellent film 24 can be blended.

  The liquid repellent film 24 preferably has a thickness of 1 nm to 30 nm. With such a thickness range, the nozzle plate 22 tends to be more excellent in liquid repellency, the film deterioration is relatively slow, and the liquid repellency can be maintained for a longer period. Moreover, it is excellent in terms of cost and ease of film formation. Further, from the viewpoint of ease of film formation, the thickness is preferably 1 nm or more and 20 nm or less, and more preferably 1 nm or more and 15 nm or less.

<Wiper unit>
3A is a perspective view showing the wiper unit 30, FIG. 3B is a side view showing the configuration of the wiper unit 30, and FIG. 3C is a positional relationship between the wiper unit 30 and the discharge port array. FIG.
The wiper unit 30 includes a wiping member 31, a feed roller 32, a material removal roller 33, a pressing roller 34, a housing 35, a wiper unit driving mechanism, and the like.

  Inside the housing 35, a pair of a feed roller 32 and a material removal roller 33 having an axis extending horizontally in the Y direction, which is the short direction of the housing 35, are arranged in the X direction, which is the longitudinal direction of the housing 35. Contained at a distance. An absorbing member (wiping member 31) for wiping off ink remaining on the surface of the nozzle plate 22 is hung between the pair of the material supply roller 32 and the material removal roller 33. The feed roller 32 feeds the wound unused wiping member 31. The material removal roller 33 winds up the used wiping member 31 that has been unwound from the material supply roller 32 and used for wiping.

A pressing roller 34 having an axis substantially parallel to the material supply roller 32 and the material removal roller 33 is exposed from the case 35 at the top of the case 35. The wiping member 31 fed out from the feed roller 32 is wound around the pressing roller 34 and wound around the material removal roller 33 after use.
In the wiper unit 30, as shown in FIG. 3C, the axial direction of the pressing roller 34 is the same as the direction in which the discharge ports 23 are arranged in the first discharge port row 50 and the second discharge port row 51. Are arranged as follows.

  The wiper unit drive mechanism (not shown) moves the wiping portion W of the wiping member 31 supported by the rotation drive of the feed roller 32 and the material removal roller 33 and the pressing roller 34 to the ink wiping position (height) of the nozzle plate 22. These functions are controlled by the control board 5.

<Wiping member>
The wiping member 31 is not particularly limited as long as it has an absorptivity with respect to the inorganic pigment-containing ink composition attached to the nozzle discharge port 23 and the nozzle plate 22, but is preferably any one that can hold a cleaning liquid described later. . Since the cleaning liquid is included in the wiping member 31, the pigment particles easily move from the surface of the wiping member 31 to the inside, and the pigment particles are less likely to remain on the surface of the wiping member 31. It is suppressed from being damaged by.

  Although it does not specifically limit as the wiping member 31, For example, a cloth, sponge, a pulp, etc. are mentioned. Among these, a fabric is preferable. If it is a fabric, it is easy to bend and it will be easier to wipe off the adhered ink. The cloth is not particularly limited, and examples thereof include those made of cupra, polyester, polyethylene, polypropylene, lyocell, rayon, and the like. At this time, it is preferable that the material of the wiping member 31 is non-woven fabric (polyester) or cupra because fuzzing is small, so that it is difficult to suck ink from the nozzle and it is difficult to cause missing dots.

  The thickness of the wiping member 31 is preferably 0.1 mm or more and 3 mm or less. When the thickness is 0.1 mm or more, it becomes easier to hold the cleaning liquid. When the thickness is 3 mm or less, the wiping member 31 is compact, the wiper unit 30 can be downsized, and the wiper unit 30 can be driven more easily.

  The surface density of the wiping member 31 is preferably 0.005 g / cm 2 or more and 0.15 g / cm 2 or less. More preferably, it is 0.02 g / cm 2 or more and 0.13 g / cm 2 or less. By being in the above range, it becomes easier to hold the cleaning liquid. Furthermore, it is preferable to use a non-woven fabric for which the surface density and thickness can be easily designed for the wiping member 31 in order to retain the cleaning liquid.

<Cleaning liquid>
The cleaning liquid applied to the nozzle plate 22 preferably contains a penetrant or a humectant. Thereby, the redispersibility of the solidified pigment particles is improved and the pigment particles are easily absorbed in the wiping member 31. The cleaning liquid is not particularly limited as long as it is applied to the nozzle plate 22. The cleaning liquid may be applied by being included in a cloth, or the cleaning liquid stored by storing the cleaning liquid on a mist or application member. May be brought into contact with the nozzle plate. Among the above-mentioned methods, it is most preferable to apply it by being included in a fabric. When the cleaning liquid is impregnated, the cloth may be impregnated with the cleaning liquid when performing the cleaning operation. That is, a cloth impregnated in advance may be used, and a mechanism for applying a cleaning liquid to the cloth before performing the cleaning operation may be provided.

  The surface tension of the cleaning liquid is preferably 45 mN / m or less, and more preferably 35 N / m or less. When the surface tension is low, the redispersibility of the inorganic pigment is improved, the permeability of the inorganic pigment to the absorbing member is improved, and the wiping property is improved. As a method for measuring the surface tension, a commonly used surface tension meter (for example, surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.) is used and measured at a liquid temperature of 25 ° C. by the Wilhelmy method. A method can be exemplified.

  The content of the cleaning liquid is preferably 10% by mass or more and 200% by mass or less, preferably 10% by mass to 120% by mass, and 30% by mass to 100% by mass with respect to 100% by mass of the absorbing member. Is more preferable. By being 10 mass% or more, it is easy to permeate | transmit inorganic pigment ink to the inner side of an absorption member, and it can suppress more that the liquid-repellent film 24 is damaged. Further, when the amount is 200% by mass or less, the remaining of the cleaning liquid in the nozzle plate 22 can be further suppressed, and dot omission caused by bubbles entering the nozzle together with the cleaning liquid, or the cleaning liquid itself entering the nozzle. Dot missing can be further suppressed.

  In addition, although it does not specifically limit as an additive (component) which can be contained in a washing | cleaning liquid, For example, resin, an antifoamer, surfactant, water, an organic solvent, a pH adjuster etc. are mentioned. Each of the above components may be used alone or in combination of two or more, and the content is not particularly limited.

  When the cleaning liquid contains an antifoaming agent, it is possible to effectively prevent the cleaning liquid remaining on the nozzle plate 22 after the cleaning process from foaming. In addition, the cleaning liquid may contain a large amount of an acidic moisturizer such as polyethylene glycol or glycerin. In this case, if the cleaning liquid contains a pH adjuster, the acidic cleaning liquid becomes an ink composition (usually pH 7.5 or higher). Basic contact) can be avoided. As a result, the ink composition can be prevented from shifting to the acidic side, and the storage stability of the ink composition is further maintained.

  In addition, the humectant that can be contained in the cleaning liquid is not particularly limited as long as it is generally usable for ink or the like. The humectant is not particularly limited, and a high-boiling humectant having a boiling point under 1 atm of preferably 180 ° C. or higher, more preferably 200 ° C. or higher can be used. When the boiling point is within the above range, the volatile component in the cleaning liquid can be prevented from volatilizing, and the inorganic pigment-containing ink composition that comes into contact with the cleaning liquid can be effectively wetted and wiped off effectively.

  Although it does not specifically limit as a high boiling point moisturizer, For example, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3 -Hexanediol, 2-methyl-2,4-pentanediol, tripropylene glycol, polyethylene glycol, polypropylene glycol, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, glycerin, mesoerythritol, pentaerythritol, etc. It is done.

  A moisturizer may be used individually by 1 type, and 2 or more types may be mixed and used for it. The content of the humectant is preferably 10 to 100% by mass with respect to the total mass (100% by mass) of the cleaning liquid. In addition, the content of the humectant being 100% by mass with respect to the total mass of the cleaning liquid indicates that all the components of the cleaning liquid are humectants.

  Of the additives that can be contained in the cleaning liquid, the penetrant will be described. Any penetrant can be used without particular limitation as long as it is generally usable for ink or the like. In a solution of 90% by weight of water and 10% by weight of the penetrant, the surface tension of the solution is 45 mN / m or less. Can be employed as a penetrant. The penetrating agent is not particularly limited, but is selected from the group consisting of, for example, alkanediols having 5 to 8 carbon atoms, glycol ethers, acetylene glycol surfactants, siloxane surfactants, and fluorine surfactants. One or more of them. The surface tension can be measured by the method described above.

  The content of the penetrant in the cleaning liquid is preferably 1% by mass or more and 40% by mass or less, and more preferably 3% by mass or more and 25% by mass or less. When the content is 1% by mass or more, the wiping property tends to be superior, and when the content is 40% by mass or less, the penetrant attacks the pigment contained in the ink near the nozzle, and the dispersion stability breaks and aggregates. Can be avoided.

<Movement mechanism>
The moving mechanism moves at least one of the wiping member 31 and the recording head 20 relative to the other, wipes the surface of the nozzle plate 22 by the wiping member 31, and adheres to the surface of the nozzle plate 22. A cleaning operation is performed to remove water. Specifically, the moving mechanism includes a carriage driving mechanism 4, a wiper unit driving mechanism, and the like, and is controlled by the control board 5.

The wiper unit drive mechanism has a pressing function of pressing the wiping member 31 against the surface of the nozzle plate 22 by relatively moving the wiping member 31 and the nozzle plate 22. A preferable pressing load is 50 gf to 700 gf, more preferably 50 gf to 500 gf, and still more preferably 75 gf to 300 gf. The pressing function may be configured to press the wiping member 31 against the nozzle plate 22 or may be configured to move the recording head 20 and press it against the wiping member 31. When the pressing force is 50 gf or more, the ink wiping property is excellent. Furthermore, even when there is a step formed between the nozzle plate 22 and the nozzle plate cover 25, it is excellent in preventing or removing ink adhering to the gap. Further, when the pressing force is 500 gf or less, the storage stability of the liquid repellent film 24 is further improved.
The load referred to here is the sum of the loads applied to the nozzle plate 22 from the entire drive mechanism.

Further, it is preferable that the moving mechanism moves the wiping member 31 and the recording head 20 relatively (X direction) at a speed of 1 cm / s or more and 10 cm / s or less after pressing. By moving within this speed range, the cleaning property and the storage stability of the liquid repellent film 24 are further improved.
This X-direction moving mechanism may be provided in either the carriage driving mechanism 4 or the wiper unit driving mechanism, or in both.

  Although the press roller 34 mentioned above is not specifically limited, For example, what was coat | covered with the elastic member is preferable. The Shore A hardness of the elastic member is preferably 10 or more and 60 or less, and more preferably 10 or more and 50 or less. Thereby, the pressing roller 34 and the wiping member 31 are bent at the time of pressing, and the wiping member 31 can be pushed into the concave portion with respect to the uneven surface of the nozzle plate 22. In particular, when there is the nozzle plate cover 25, the wiping member 31 can be pushed deeply into the corner (gap) between the nozzle plate 22 and the nozzle plate cover 25 protruding from the nozzle plate 22, thereby accumulating ink. Can be suppressed. Therefore, the cleaning property is further improved.

<Ink composition>
Next, is it included in an ink composition containing an inorganic pigment (hereinafter referred to as an inorganic pigment-containing ink composition) and an ink composition containing a coloring material other than the inorganic pigment (hereinafter referred to as an inorganic pigment-free ink composition)? The additives (components) that can be included are described. The ink composition includes a color material (such as an inorganic pigment, an organic pigment, or a dye), a solvent (such as water or an organic solvent), a resin, a surfactant, and the like.

<Color material>
Inorganic pigment containing ink composition is one containing inorganic pigments in the range of 1.0 mass% or more 20.0% by mass as a colorant. In particular, when the inorganic pigment-containing ink composition is a white ink composition, the inorganic pigment concentration is preferably 5% by mass or more.
Further, the inorganic pigment-free ink composition may contain a color material selected from pigments and dyes other than inorganic pigments.

<Pigment>
The inorganic pigment contained in the inorganic pigment-containing ink composition preferably has an average particle diameter of 20 nm to 250 nm, more preferably 20 nm to 200 nm.
Moreover, it is preferable that the needle-shaped ratio of an inorganic pigment is 3.0 or less. By adopting such a needle-like ratio, the present invention can satisfactorily protect the liquid repellent film. The acicular ratio is a value obtained by dividing the maximum length of each particle by the minimum width (acicular ratio = maximum length of particle / minimum width of particle). The specification of the needle ratio can be measured using a transmission electron microscope.
Further, the Mohs hardness of the inorganic pigment is more than 2.0 and preferably 5 or more and 8 or less.

  Examples of inorganic pigments include simple metals such as carbon black, gold, silver, copper, aluminum, nickel, and zinc; cerium oxide, chromium oxide, aluminum oxide, zinc oxide, magnesium oxide, silicon oxide, tin oxide, zirconium oxide, Oxides such as iron oxide and titanium oxide; sulfates such as calcium sulfate, barium sulfate and aluminum sulfate; silicates such as calcium silicate and magnesium silicate; nitrides such as boron nitride and titanium nitride; silicon carbide and titanium carbide And carbides such as boron carbide, tungsten carbide, and zirconium carbide; borides such as zirconium boride and titanium boride. Among these, preferable inorganic pigments include aluminum, aluminum oxide, titanium oxide, zinc oxide, zirconium oxide, silicon oxide and the like. More preferably, titanium oxide, silicon oxide, and aluminum oxide are mentioned. In titanium oxide, the rutile type has a Mohs hardness of about 7 to 7.5, and the anatase type has a range of 6.6 to 6. Rutile titanium oxide is low in production cost, is a preferred crystal system, and can exhibit good whiteness. Therefore, when rutile type titanium dioxide is used, an ink jet recording apparatus having liquid repellent film storage stability and capable of producing a recorded matter with good whiteness at low cost.

  The organic pigment is not particularly limited. Examples include perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments. It is done. Specific examples of the organic pigment include the following.

  Examples of pigments used for cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15:34, 16, 18, 22, 60, 65, 66, C.I. I. Bat Blue 4, 60 and the like. Among them, C.I. I. At least one of CI Pigment Blue 15: 3 and 15: 4 is preferable.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, 254, 264, C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50 and the like. Among them, C.I. I. Pigment red 122, C.I. I. Pigment red 202, and C.I. I. One or more selected from the group consisting of Pigment Violet 19 is preferred.

Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180, 185, 213 and the like. Among them, C.I. I. One or more selected from the group consisting of CI Pigment Yellow 74, 155, and 213 are preferred.
In addition, as a pigment used for inks of colors other than the above, such as green ink and orange ink, conventionally known pigments can be used.

The average particle diameter of the pigments other than the inorganic pigment is preferably 250 nm or less because clogging at the nozzle can be suppressed and ejection stability is further improved.
In addition, the average particle diameter in this specification is based on a volume. As a measuring method, for example, it can be measured by a particle size distribution measuring apparatus using a laser diffraction scattering method as a measurement principle. Examples of the particle size distribution measuring device include a particle size distribution meter (for example, Microtrac UPA manufactured by Nikkiso Co., Ltd.) having a dynamic light scattering method as a measurement principle.

<Dye>
A dye can be used as the coloring material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used.

  The content of the color material is preferably 0.4 to 12% by mass, and more preferably 2 to 5% by mass with respect to the total mass (100% by mass) of the ink composition.

<Resin>
Examples of the resin include a resin dispersant, a resin emulsion, and a wax. Among these, emulsions are preferred because they have good adhesion and abrasion resistance.

The inorganic pigment-containing ink composition preferably has the following characteristics (1) or (2) in terms of composition.
(1) The ink composition for ink jet recording contains a first resin having a heat distortion temperature of 10 ° C. or less (hereinafter referred to as “first ink”).
(2) The ink composition for inkjet recording contains the second resin and does not substantially contain glycerin (hereinafter referred to as “second ink”).

  These ink compositions tend to solidify on the nozzle forming surface and the absorbing member and tend to promote damage to the liquid repellent film. However, the present invention can satisfactorily prevent this.

  The first ink contains a first resin having a heat distortion temperature of 10 ° C. or lower. Such a resin has a property of firmly adhering to a material rich in flexibility and absorbability such as a fabric. On the other hand, coating and solidification proceed rapidly, and adhere to the nozzle forming surface and the absorbent material as solid matter.

  The second ink substantially does not contain glycerin having a boiling point of 290 ° C. under 1 atm. If the colored ink substantially contains glycerin, the drying property of the ink is greatly reduced. As a result, in various recording media, in particular, recording media with non-ink-absorbing properties or low-absorbing properties, not only unevenness in image density but also ink fixing properties cannot be obtained. In addition, since glycerin is not contained, moisture or the like as a main solvent in the ink rapidly volatilizes, and the ratio of the organic solvent in the second ink increases. In this case, the thermal deformation temperature (particularly the film increasing temperature) of the resin is lowered, and solidification by the film is further promoted. Furthermore, it is preferable that substantially no alkyl polyols (excluding the above-mentioned glycerin) having a boiling point of 280 ° C. or higher at 1 atm. In the case of the second ink, in the case of a recording apparatus having a heating mechanism for heating the recording medium conveyed to a position facing the recording head, the ink in the vicinity of the recording head is dried, and the problem becomes more prominent. However, if it is this invention, it can prevent favorably. The heating temperature is preferably 30 ° C. or higher and 80 ° C. or lower from the viewpoints of ink storage stability and recorded image quality. The heating mechanism is not particularly limited, and examples include a heater, a hot air heater, and an infrared heater.

  Here, “substantially free” in the present specification means not to contain more than the amount that fully exhibits the significance of addition. Speaking quantitatively, it is preferable that glycerin does not contain 1.0 mass% or more with respect to the total mass (100 mass%) of the colored ink, and more preferably does not contain 0.5 mass% or more. It is more preferable not to contain 0.1% by mass or more, even more preferable not to contain 0.05% by mass or more, particularly preferable not to contain 0.01% by mass or more, and not to contain 0.001% by mass or more. Most preferred.

  The heat deformation temperature of the first resin is 10 ° C. or less. Furthermore, it is preferably −10 ° C. or lower, and more preferably −15 ° C. or lower. When the glass transition temperature of the fixing resin is within the above range, the fixability of the pigment in the recorded matter is further improved, and as a result, the abrasion resistance is improved. In addition, although it does not specifically limit about the minimum of heat deformation temperature, It is good in it being -50 degreeC or more.

  The thermal deformation temperature of the second resin is less likely to cause clogging of the head and can improve the abrasion resistance of the recorded matter. Therefore, the lower limit is preferably 40 ° C. or higher, and preferably 60 ° C. or higher. It is more preferable. A preferable upper limit is 100 ° C. or lower.

  Here, the “thermal deformation temperature” in the present specification is a temperature value represented by a glass transition temperature (Tg) or a minimum film forming temperature (MFT). That is, “the thermal deformation temperature is 40 ° C. or higher” means that either Tg or MFT may be 40 ° C. or higher. In addition, since MFT can grasp | ascertain the superiority or inferiority of the redispersibility of resin rather than Tg, it is preferable that the said heat deformation temperature is a temperature value represented by MFT. If the ink composition is excellent in resin redispersibility, the ink composition does not adhere and the head is less likely to be clogged.

  Tg in this specification is described as a value measured by a differential scanning calorimetry method. Further, MFT in this specification is described as a value measured by ISO 2115: 1996 (title: plastic-polymer dispersion-measurement of white point temperature and minimum film forming temperature).

<Resin dispersant>
When the ink composition contains the pigment, the ink composition may contain a resin dispersant so that the pigment can be stably dispersed and held in water. When the ink composition includes a pigment dispersed using a resin dispersant such as a water-soluble resin or a water-dispersible resin (hereinafter referred to as “resin-dispersed pigment”), the ink composition adheres to the recording medium 10. In this case, at least one of the adhesion between the recording medium 10 and the ink composition and the solidified material in the ink composition can be improved. Among the resin dispersants, a water-soluble resin is preferable because of excellent dispersion stability.

<Resin emulsion>
The ink composition may contain a resin emulsion. By forming a resin film, the resin emulsion exhibits an effect of sufficiently fixing the ink composition on the recording medium 10 and improving the abrasion resistance of the image. The recorded matter recorded using the ink composition containing the resin emulsion due to the above effects is excellent in adhesion and abrasion resistance, particularly on the fabric, the ink non-absorbing or low-absorbing recording medium 10. Become. On the other hand, although it tends to promote solidification of the inorganic pigment, the present invention can satisfactorily prevent the problem of deterioration of the liquid repellent film caused by wiping off the solidified deposit.

  The resin emulsion functioning as a binder is preferably contained in the ink composition in an emulsion state. By including a resin functioning as a binder in the ink composition in an emulsion state, it is easy to adjust the viscosity of the ink composition to an appropriate range in the ink jet recording system, and the storage stability and ejection stability of the ink composition. It will be excellent.

  The resin emulsion is not particularly limited. For example, (meth) acrylic acid, (meth) acrylic ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone, Examples thereof include homopolymers or copolymers of vinylpyridine, vinylcarbazole, vinylimidazole, and vinylidene chloride, fluororesins, and natural resins. Among them, at least one of (meth) acrylic resin and styrene- (meth) acrylic acid copolymer resin is preferable, and at least one of acrylic resin and styrene-acrylic acid copolymer resin is more preferable, styrene. -Acrylic acid copolymer resin is more preferable. The above copolymer may be in any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer.

  The resin emulsion may be a commercially available product or may be prepared using an emulsion polymerization method or the like as follows. As a method for obtaining the resin in the ink composition in an emulsion state, the above-mentioned water-soluble resin monomer is emulsion-polymerized in water containing a polymerization catalyst and an emulsifier. The polymerization initiator, the emulsifier, and the molecular weight modifier used in the emulsion polymerization can be used according to a conventionally known method.

  The average particle size of the resin emulsion is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 20 nm to 300 nm, in order to further improve the storage stability and ejection stability of the ink.

  A resin emulsion may be used individually by 1 type, and may be used in combination of 2 or more type. Among the resins, the content of the resin emulsion is preferably in the range of 0.5 to 15% by mass with respect to the total mass (100% by mass) of the ink composition. When the content is within the above range, the solid content concentration can be lowered, so that the discharge stability can be further improved.

<Wax>
The ink composition may contain a wax. By including the wax in the ink composition, the ink composition is more excellent in fixability on the non-ink-absorbing and low-absorbing recording medium 10. Among the waxes, an emulsion or suspension type is more preferable. Examples of the wax include, but are not limited to, polyethylene wax, paraffin wax, and polypropylene wax. Among them, polyethylene wax described later is preferable.

  When the ink composition contains polyethylene wax, the ink can have excellent abrasion resistance.

  The average particle diameter of the polyethylene wax is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 50 nm to 200 nm, in order to further improve the storage stability and ejection stability of the ink.

  The polyethylene wax content (in terms of solid content) is preferably in the range of 0.1 to 3% by mass and more preferably in the range of 0.3 to 3% by mass with respect to the total mass (100% by mass) of the ink composition. The range of 0.3 to 1.5% by mass is more preferable. When the content is in the above range, the ink composition can be solidified and fixed satisfactorily on the recording medium 10, and the storage stability and ejection stability of the ink are further improved.

<Antifoaming agent>
The ink composition preferably contains an antifoaming agent. More specifically, it is preferable that at least one of the cleaning liquid included in the ink composition or the wiping member 31 includes an antifoaming agent. When the ink composition contains an antifoaming agent, it is possible to prevent foaming, and as a result, it is possible to prevent a problem that bubbles enter the nozzle.

  Examples of the antifoaming agent include, but are not limited to, a silicon-based antifoaming agent, a polyether-based antifoaming agent, a fatty acid ester-based antifoaming agent, and an acetylene glycol-based antifoaming agent. Among these, a silicon-based antifoaming agent and an acetylene glycol-based antifoaming agent are preferable because they are excellent in ability to appropriately maintain surface tension and interfacial tension and hardly generate bubbles. Moreover, as for the HLB value based on the Griffin method of an antifoamer, 5 or less is more preferable.

<Surfactant>
The ink composition may contain a surfactant (excluding those listed as the antifoaming agent. That is, the ink composition is limited to those having an HLB value of more than 5 by the Griffin method). Examples of the surfactant include, but are not limited to, nonionic surfactants. The nonionic surfactant has an action of spreading the ink uniformly on the recording medium 10. Therefore, when ink jet recording is performed using an ink containing a nonionic surfactant, a high-definition image with almost no bleeding can be obtained. Examples of such nonionic surfactants include, but are not limited to, silicon-based, polyoxyethylene alkyl ether-based, polyoxypropylene alkyl ether-based, polycyclic phenyl ether-based, sorbitan derivatives, and fluorine-based interfaces. Examples of the surfactant include silicon surfactants.

  The silicon-based surfactant is excellent in the effect of spreading the ink uniformly so as not to cause bleeding on the recording medium 10 as compared with other nonionic surfactants.

  Surfactant may be used individually by 1 type, and 2 or more types may be mixed and used for it. The surfactant content is further improved in the storage stability and ejection stability of the ink, and is 0.1% by mass or more and 3% by mass or less with respect to the total mass (100% by mass) of the ink. A range is preferable.

<Water>
The ink composition may contain water. In particular, when the ink composition is a water-based ink, water is a main medium of the ink, and is a component that evaporates and scatters when the recording medium 10 is heated in ink jet recording.

Examples of water include water from which ionic impurities have been removed as much as possible, such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. Further, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, generation of mold and bacteria can be prevented when the pigment dispersion and ink using the same are stored for a long period of time.
The water content is not particularly limited, and may be appropriately determined as necessary.

<Surface tension of ink composition>
The surface tension of the ink composition is not particularly limited, but is preferably 15 to 35 mN / m. As a result, it is possible to ensure the permeability of the ink composition to the absorbing member and the ability to prevent bleeding when recording, and the ink wiping property during the cleaning operation is improved. As described above, a method of measuring the surface tension of the ink composition using a generally used surface tension meter (for example, a surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.) can be exemplified. Further, the difference between the surface tension of the ink composition and the surface tension of the cleaning liquid preferably has a relationship of 10 mN / m or less. Thereby, when both are mixed in the vicinity of the nozzle, it is possible to prevent the surface tension of the ink composition from being extremely lowered.

In the ink jet recording apparatus 1 having the basic configuration described above, a specific embodiment of the present invention when the above ink composition is used will be described below.
As described above, the inkjet recording apparatus 1 includes the nozzle plate 22, the wiping member 31 that wipes the surface of the nozzle plate 22, and the above-described moving mechanism that changes the relative position of the nozzle plate 22 and the wiping member 31. Yes. The nozzle plate 22 includes a first discharge port array 50 in which the discharge ports 23 of the plurality of nozzles 21 that discharge the inorganic pigment-containing ink composition are arranged, and discharges of the plurality of nozzles 21 that discharge the inorganic pigment-free ink composition. And a second discharge port array 51 in which the outlets 23 are arranged.

(Embodiment 1)
In the inkjet recording apparatus 1 according to the first embodiment, in the series of operations in which the surface of the nozzle plate 22 is wiped by the wiping member 31, the first discharge port array 50 and the first discharge port array 51 are preferentially wiped. The two discharge port arrays 51 are arranged. This will be specifically described below.

FIG. 4A is a plan view of the nozzle plate 22 (hereinafter referred to as nozzle plate 22a) according to the first embodiment as viewed from the discharge port 23 side.
The nozzle plate 22 a includes n first ejection port arrays 50 and m second ejection port arrays 51. In addition, n first discharge port arrays 50 are continuously arranged on one side (+ X side in FIG. 4A) of the nozzle plate 22a (that is, n consecutive from one end portion). ing. In the nozzle plate 22a, m nozzle rows 22a are continuously arranged on the other side (the −X side in FIG. 4A) (that is, m pieces are continuously arranged from the other end). Yes.

<Wiping operation>
In such an arrangement of the discharge port arrays in the nozzle plate 22a, a series of wiping operations are performed as follows.

In the moving mechanism, first, the wiping portion W (see FIG. 3B) where the wiping member 31 is exposed from the housing 35 of the wiper unit 30 is moved to the other end of the nozzle plate 22a (− in FIG. 4A). The wiping member 31 and the nozzle plate 22a are relatively moved so as to come to the end on the X side.
Next, the wiper unit drive mechanism moves the wiping portion W so as to contact the surface of the nozzle plate 22a with a predetermined pressing force.

Next, the wiping portion W of the wiping member 31 moves in the direction indicated by the arrow in FIG. 4A (the + X direction toward one end of the nozzle plate 22a) with respect to the nozzle plate 22a to move the nozzle plate 22a. The wiper unit 30 and the nozzle plate 22a are relatively moved so as to wipe the surface.
As a result, the wiping portion W of the wiping member 31 first wipes the second discharge port array 51, and the remaining (m−1) second discharge port arrays 51 continuously thereafter the first discharge port array 50. Will be wiped with priority. After all the second discharge port arrays 51 are wiped, the n first discharge port arrays 50 are continuously wiped.

  After all (n + m) discharge port arrays have been wiped, the wiper unit drive mechanism moves the wiping member 31 away from the nozzle plate 22a, and drives the feed roller 32 and the material removal roller 33 to renew the wiping member 31. The surface is pulled out from the feed roller 32 side to be exposed, and the wiped surface is sent to the material removal roller 33 side to be wound up.

  This series of wiping operations is controlled by a control board 5 provided in the inkjet recording apparatus 1.

As described above, according to the ink jet recording apparatus 1 according to the present embodiment, the following effects can be obtained.
When the surface of the nozzle plate 22 is wiped by the wiping member 31, ejection failure due to thickening of the ink composition or adhesion of foreign matter to the nozzle plate 22 is prevented or reduced. In a series of wiping operations in which the surface of the nozzle plate 22 is wiped by the wiping member 31, the second discharge port array 51 from which the ink composition containing the color material other than the inorganic pigment is discharged is preferentially wiped. The first discharge port array 50 from which the ink composition containing the inorganic pigment is discharged is wiped off. Since the second discharge port array 51 is wiped preferentially, the state in which the inorganic pigment is interposed between the wiping member 31 and the surface of the nozzle plate 22 is reduced in a series of wiping operations. When the first discharge port array 50 is wiped, the surface of the nozzle plate 22 is damaged in the vicinity of the first discharge port array 50 because the inorganic pigment may be pressed against the surface of the nozzle plate 22 by the wiping member 31 and rubbed. In some cases, the second discharge port array 51 is wiped preferentially in a state where no inorganic pigment is present, so that damage to the surface of the nozzle plate 22 is suppressed.

  Thus, according to the present embodiment, the inorganic pigment discharged from the first discharge port array 50 and adhering to the nozzle plate 22 is applied to the second discharge port array 51 and damages the entire surface of the nozzle plate 22. This can be eliminated, and the degree of damage can be reduced. As a result, even when the liquid repellent film 24 is provided on the surface of the nozzle plate 22, the deterioration of the liquid repellent film 24 over the entire nozzle plate 22 is suppressed, so that the ejection of the ink composition is more stable. Can be maintained.

  Further, in the wiping operation in which the relative position between the nozzle plate 22 and the wiping member 31 varies in a single direction, the first discharge port array 50 and the second discharge port are preferentially wiped off the second discharge port array 51. Since the row 51 is arranged, the above effect can be obtained by a simple wiping operation.

(Embodiment 2)
Next, the ink jet recording apparatus 1 according to the second embodiment will be described. In the description, the same components as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.
In the second embodiment, in n first ejection port arrays 50 and m second ejection port arrays 51, k = (n + m) / 2 when n + m is an even number, and k = when n + m is an odd number. In a series of operations in which the wiping member 31 wipes the surface of the nozzle plate 22 from the first to the (n + m) th first ejection port array 50 or the second ejection port array 51 when (n + m−1) / 2, k + 1 The first discharge port array 50 and the second discharge port array 51 are arranged so that the n first discharge port arrays 50 are wiped in the range from the nth to the (n + m) th. This will be specifically described below.

FIG. 4B is a plan view of the nozzle plate 22 (hereinafter referred to as nozzle plate 22b) according to the second embodiment as viewed from the discharge port 23 side.
The second embodiment is the same as the first embodiment except that the arrangement of the first discharge port array 50 and the second discharge port array 51 in the nozzle plate 22b is different from that in the nozzle plate 22a.
In the first embodiment, n first ejection port arrays 50 are arranged in succession from one end of the nozzle plate 22a, and the second ejection port array 51 is m from the other end of the nozzle plate 22a. It has been described as being continuously arranged. On the other hand, in the nozzle plate 22b, the n first ejection port arrays 50 and the m second ejection port arrays 51 are not necessarily arranged continuously. As shown in FIG. 4B, several second discharge port arrays 51 are inserted between the n first discharge port arrays 50. However, the n first ejection port arrays 50 are arranged in the order of k + 1st to n + m from the first (row at the other end of the nozzle plate 22b) to the n + mth (row at the one end of the nozzle plate 22b). The first ejection port arrays 50 for n columns are arranged in the range up to the th. In other words, the first discharge port arrays 50 in which the discharge ports 23 for discharging the inorganic pigment-containing ink composition are arranged are all arranged in the columns after the substantially middle (between the k-th and k + 1-th or the k + 1-th middle). Has been.

According to the ink jet recording apparatus 1 according to the present embodiment, the following effects can be obtained.
In a series of wiping operations in which the surface of the nozzle plate 22 is wiped by the wiping member 31, all of the first discharge port arrays 50 to which the ink composition containing the inorganic pigment is discharged are in the second half (k + 1 to n + m). In the first range). By being wiped in the latter half, the state in which the inorganic pigment is interposed between the wiping member 31 and the surface of the nozzle plate 22 is reduced in a series of wiping operations.
That is, according to the present embodiment, the inorganic pigment discharged from the first discharge port array 50 and attached to the nozzle plate 22 damages the entire surface of the nozzle plate 22 while being spread on the second discharge port array 51. And the degree of damage can be reduced. As a result, even when the surface of the nozzle plate 22 is provided with the liquid repellent film 24 and the like, the deterioration of the liquid repellent film over the entire nozzle plate is suppressed, so that the ejection of the ink composition is made more stable. Can be maintained.

(Embodiment 3)
Next, the ink jet recording apparatus 1 according to Embodiment 3 will be described. In the description, the same components as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.
In the third embodiment, in n first ejection port arrays 50 and m second ejection port arrays 51, k = (n + m) / 2 when n + m is an even number, and k = when n + m is an odd number. In a series of operations in which the wiping member 31 wipes the surface of the nozzle plate 22 from the first to the (n + m) th first ejection port array 50 or the second ejection port array 51 when (n + m−1) / 2. The first discharge port array 50 so that the rate at which the first discharge port array 50 is wiped in the range from the kth to the kth is smaller than the rate at which the first discharge port array 50 is wiped in the range from the (k + 1) th to the n + mth. And the second discharge port array 51 are arranged.

FIG. 4C is a plan view of the nozzle plate 22 (hereinafter referred to as nozzle plate 22 c) according to the third embodiment as viewed from the discharge port 23 side.
The third embodiment is the same as the first embodiment except that the arrangement of the first discharge port array 50 and the second discharge port array 51 in the nozzle plate 22c is different from that in the nozzle plate 22a.
In the first embodiment, n first ejection port arrays 50 are arranged in succession from one end of the nozzle plate 22a, and the second ejection port array 51 is m from the other end of the nozzle plate 22a. It has been described as being continuously arranged. On the other hand, in the nozzle plate 22c, the n first ejection port arrays 50 and the m second ejection port arrays 51 are not necessarily arranged continuously. As shown in FIG. 4C, several second discharge port arrays 51 are inserted between the n first discharge port arrays 50 arranged from one end. Similarly, several first discharge port arrays 50 are inserted between the m second discharge port arrays 51 arranged from the other end. However, the ratio of the first discharge port arrays 50 in the range from the first to the kth array is arranged to be smaller than the ratio of the first discharge port arrays 50 in the range from the (k + 1) th to the n + mth array. Has been.

According to the ink jet recording apparatus 1 according to the present embodiment, the following effects can be obtained.
In a series of wiping operations in which the surface of the nozzle plate 22 is wiped by the wiping member 31, the rate at which the first discharge port array 50 is wiped in the first half (range from the first to the kth) in the wiping order is the latter half (k + 1). To the n + mth range) is smaller than the rate at which the first discharge port array 50 is wiped. In other words, the second discharge port array 51 is wiped preferentially so that the rate at which the second discharge port array 51 is wiped in the first half is increased. Since the second discharge port array 51 is wiped preferentially, the state in which the inorganic pigment is interposed between the wiping member 31 and the surface of the nozzle plate 22 is reduced in a series of wiping operations.

  Thus, according to the present embodiment, the inorganic pigment discharged from the first discharge port array 50 and adhering to the nozzle plate 22 damages the entire surface of the nozzle plate while being spread on the second discharge port array 51. The state becomes less and the degree of damage can be reduced. As a result, for example, even when the surface of the nozzle plate 22 is provided with the liquid repellent film 24 and the like, the deterioration of the liquid repellent film over the entire nozzle plate 22 is suppressed, so that the ejection of the ink composition is more stable. Can be maintained.

(Embodiment 4)
Next, the ink jet recording apparatus 1 according to the fourth embodiment will be described. In the description, the same components as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.
In the fourth embodiment, in a series of operations in which the surface of the nozzle plate 22 is wiped by the wiping member 31, the relative position between the nozzle plate 22 and the wiping member 31 is changed so that the second discharge port array 51 is wiped preferentially. It is characterized by that. This will be specifically described below.

5A to 5C are plan views of an example of the nozzle plate 22 (hereinafter referred to as nozzle plate 22d) according to the fourth embodiment, as viewed from the discharge port 23 side.
The arrangement of the first ejection port array 50 and the second ejection port array 51 in the nozzle plate 22d is not limited as in the nozzle plate 22a, and the wiping operation by the moving mechanism is not limited to a certain direction. Except for this point, the fourth embodiment is the same as the first embodiment.

In the first embodiment, n first ejection port arrays 50 are arranged in succession from one end of the nozzle plate 22a, and the second ejection port array 51 is m from the other end of the nozzle plate 22a. It has been described as being continuously arranged. On the other hand, in the nozzle plate 22d, the arrangement of the first ejection port array 50 and the second ejection port array 51 is not particularly limited.
For example, in the example of the nozzle plate 22d shown in FIG. 5A, two first discharge port arrays 50 are arranged at both ends of the nozzle plate 22d. The second ejection port array 51 is continuously arranged in a range sandwiched between the first ejection port arrays 50 in both end regions.

<Wiping Operation in Embodiment 4>
With respect to the above arrangement, a series of wiping operations are performed as follows.

In the moving mechanism, first, the wiping portion W (see FIG. 3B) where the wiping member 31 is exposed from the housing 35 of the wiper unit 30 is moved to the other end of the nozzle plate 22d (− in FIG. 5A). The wiping member 31 and the nozzle plate 22d are relatively moved so as to come to the position of the second discharge port array 51 closest to the X-side end portion.
Next, the wiper unit drive mechanism moves the wiping portion W so as to contact the surface of the nozzle plate 22d with a predetermined pressing force.

Next, the wiping portion W of the wiping member 31 moves relative to the nozzle plate 22d in the direction indicated by the arrow A in FIG. 5A (the + X direction toward one end of the nozzle plate 22d) to move the nozzle plate 22d. The wiper unit 30 and the nozzle plate 22d are relatively moved so as to wipe the surface.
After the two first discharge port arrays 50 arranged at one end are wiped, the wiper unit drive mechanism separates the wiping member 31 from the nozzle plate 22d, and the moving mechanism is configured such that the wiping unit W is at the other end. The wiping member 31 and the nozzle plate 22d are relatively moved so as to come to the position of the first discharge port array 50 which is the closest of the two first discharge port arrays 50 arranged in the section.
Next, the wiper unit drive mechanism moves the wiping portion W so as to contact the surface of the nozzle plate 22d with a predetermined pressing force.

Next, the wiping portion W of the wiping member 31 moves relative to the nozzle plate 22d in the direction indicated by the arrow B in FIG. 5A (the -X direction toward the other end of the nozzle plate 22d). The wiper unit 30 and the nozzle plate 22d are relatively moved so as to wipe the surface of 22d.
After the two first discharge port arrays 50 arranged at the other end are wiped, the wiper unit drive mechanism moves the wiping member 31 away from the nozzle plate 22d and drives the supply roller 32 and the material removal roller 33. Then, a new surface of the wiping member 31 is pulled out from the supply roller 32 side to be exposed, and the wiped surface is sent to the material removal roller 33 side to be wound up.
By the series of wiping operations described above, the second discharge port array 51 is first wiped with priority, and then the first discharge port array 50 is wiped continuously.

Further, for example, in the example of the nozzle plate 22d shown in FIG. 5B, the first discharge port arrays 50 are arranged at both ends and the center of the nozzle plate 22d. The second ejection port array 51 is continuously arranged in a range sandwiched between the first ejection port array 50 in the both end regions and the first ejection port array 50 in the central portion.
For such an arrangement, a series of wiping operations are performed in the order of ABCD as indicated by arrows A to D shown in FIG. Arrows A to D are areas in which the wiping portion W moves so as to wipe the surface of the nozzle plate 22d. Between the arrows, the wiping portion W is temporarily moved to the nozzle plate 22d by the wiper unit driving mechanism as described above. It is moved away from the surface by a moving mechanism.

Further, for example, in the example of the nozzle plate 22d shown in FIG. 5C, the first discharge port arrays 50 are arranged in the regions at both ends of the nozzle plate 22d. However, a portion in which the first discharge port array 50 is alternately arranged with the second discharge port array 51 is also included.
For such an arrangement, a series of wiping operations are performed in the order of A to F as indicated by arrows A to F shown in FIG. Arrows A to F are areas in which the wiping portion W moves so as to wipe the surface of the nozzle plate 22d. Between the arrows, the wiping portion W is temporarily moved to the nozzle plate 22d by the wiper unit driving mechanism as described above. It is moved away from the surface by a moving mechanism.

However, when the second discharge port array 51 is divided into a large number of regions as described above, the wiping operation controlled by the moving mechanism and the wiper unit driving mechanism becomes complicated, and the wiping is efficiently performed. Not done. In such a case, for example, as indicated by arrows H and I shown in FIG. However, in this case, in the series of wiping operations, as in the second embodiment, the n first ejection port arrays 50 are wiped in the range from the (k + 1) th to the (n + m) th, or at least As in the third embodiment, the rate at which the first discharge port array 50 is wiped in the range from the first to the kth is smaller than the rate at which the first discharge port array 50 is wiped in the range from the (k + 1) th to the n + mth. It is necessary to become.
In this way, the position and order of wiping are appropriately set according to the arrangement of the first discharge port array 50 and the second discharge port array 51 in the nozzle plate 22d.

  According to this embodiment, in a series of wiping operations, the first ejection port array 50 that ejects an ink composition containing an inorganic pigment, and the second ejection port that ejects an ink composition containing a color material other than the inorganic pigment. In accordance with the arrangement of the rows 51, the moving mechanism changes the relative position between the nozzle plate 22 and the wiping member 31 so that the second discharge port rows 51 are wiped preferentially. In other words, the second discharge port array 51 is wiped preferentially regardless of the arrangement of the first discharge port array 50 and the second discharge port array 51. For example, in order to enable high-definition images to be recorded at high speed, the plurality of first discharge port arrays 50 are arranged at positions separated from each other with the plurality of second discharge port arrays 51 interposed therebetween. Even if, conversely, even if the first discharge port array 50 is sandwiched between the second discharge port array 51, the relative position between the nozzle plate 22 and the wiping member 31 fluctuates, giving priority. Thus, wiping is performed so that the second discharge port array 51 is wiped off. As a result, the same effects as those of the above-described embodiment can be obtained, and the ejection of the ink composition can be maintained in a more stable state.

  As described above, according to the present embodiment, the arrangement of the nozzle ejection ports 23 in the nozzle plate 22, that is, the arrangement of the nozzle arrays in the recording head 20 can be performed without regard to the order of wiping. Since the arrangement giving priority to the accuracy, the recording speed, and the like can be provided, it is possible to provide an ink jet recording apparatus that can record a higher-definition image at a high speed and is more excellent in ejection stability.

(Modification 1)
FIGS. 6A and 6B are plan views of an example of the nozzle plate 22d according to the modification as viewed from the discharge port 23 side.
In the first embodiment, after the wiping of the nozzle plate 22 is completed by a series of operations, the wiper unit drive mechanism drives the material supply roller 32 and the material removal roller 33 so that the new surface of the wiping member 31 is on the material roller 32 side. It was explained that it was pulled out from the surface and exposed, and the wiped surface was sent to the material removal roller 33 side to be wound up. That is, the wiping portion W of the wiping member 31 has been described so as not to change until a series of wiping operations are completed. However, the present invention is not limited to this, and the wiping portion W is refreshed during the wiping operation (of the wiping member 31). Exposing new surfaces).

The nozzle plate 22d shown in FIG. 6A is an example in which two rows of first ejection port arrays 50 are arranged at both ends of the nozzle plate 22d, similarly to the example of the nozzle plate 22d shown in FIG. It is. The second ejection port array 51 is continuously arranged in a range sandwiched between the first ejection port arrays 50 in both end regions.
In such an arrangement, wiping can be efficiently performed by refreshing the wiping portion W during the wiping operation. Specifically, when the wiping unit W is refreshed after wiping the first discharge port array 50, the second discharge port array 51 can be continuously wiped well. Wiping toward both ends of the nozzle plate 22d can be performed with the second discharge port array 51 arranged at the center of the nozzle plate 22d as a base as indicated by arrows A and B shown in a). As a result, for example, in the case of the nozzle plate 22d having the arrangement shown in FIG. 6A, wiping from the central portion toward both ends can be performed in a well-balanced manner. In addition, wiping can be performed efficiently, for example, by reducing the moving distance for the series of wiping (the amount of change in the relative position between the nozzle plate 22 and the wiping member 31).

The nozzle plate 22d shown in FIG. 6B is similar to the example of the nozzle plate 22d shown in FIG. 5C in that the first discharge port arrays 50 are arranged in the regions at both ends of the nozzle plate 22d. This is an example in which the first discharge port array 50 also includes portions alternately arranged with the second discharge port array 51.
Even in such an arrangement, the wiping can be efficiently performed by refreshing the wiping portion W during the wiping operation, as described above. Specifically, as shown by arrows E and F shown in FIG. 6B, wiping is performed toward both ends of the nozzle plate 22d with the second discharge port array 51 disposed at the center of the nozzle plate 22d as a base point.

However, when the na first ejection port arrays 50 and the ma second ejection port arrays 51 are wiped in the direction of the arrow E, the following conditions are satisfied.
When na + ma is an even number, ka = (na + ma) / 2, and when na + ma is an odd number, when ka = (na + ma-1) / 2, the first discharge port of the na row in the range from ka + 1 to na + math. The first outlet row 50 and the second outlet row 51 are arranged so that the row 50 is wiped. Alternatively, the first discharge port array 50 is wiped at least from the first to the kath, so that the first discharge port array 50 is wiped from the first to the (na + 1) th to na + math.

In the case of wiping in the direction of the arrow F, when the nb first discharge port arrays 50 and the mb second discharge port arrays 51 are wiped, the following is satisfied.
When nb + mb is an even number, kb = (nb + mb) / 2, and when nb + mb is an odd number, when kb = (nb + mb−1) / 2, the first discharge ports in the nb row in the range of kb + 1 to nb + mb The first outlet row 50 and the second outlet row 51 are arranged so that the row 50 is wiped. Alternatively, the first discharge port arrays 50 are arranged so that the rate at which the first discharge port arrays 50 are wiped from the first to the kbth is smaller than the rate at which the first discharge port arrays 50 are wiped from the kb + 1th to the nb + mbth.

  Since the second discharge port array 51 is wiped preferentially as described above, the state in which the inorganic pigment is interposed between the wiping member 31 and the surface of the nozzle plate 22 is reduced in a series of wiping operations. As a result, damage to the surface of the nozzle plate 22 is suppressed.

(Experimental example)
An experimental example will be described below. The present invention is not limited by the following experimental examples.

<Ink composition>
The main materials for the ink composition are as follows.
[Color material]
・ C. I. Pigment Black 7
(Carbon black, average particle size 100 nm, Mohs hardness 1 to 2.0)
・ C. I. Pigment Blue 15: 3 (average particle diameter 100 nm, Mohs hardness 1 or less)
・ C. I. Pigment Red 122 (average particle size 120 nm, Mohs hardness 1 or less)
・ C. I. Pigment Yellow 155 (average particle size 200 nm, Mohs hardness 1 or less)
・ Titanium dioxide (average particle size 350 nm, Mohs hardness 7.2)
〔Organic solvent〕
・ 1,2-Hexanediol ・ 2-Pyrrolidone ・ Propylene glycol [Resin emulsion]
-Styrene-acrylic acid copolymer resin emulsion (Tg 85 ° C, average particle size 140 nm)
[Polyethylene wax]
・ AQUACER 515 (trade name, manufactured by BYK)
[Silicon surfactant]
・ BYK348 (Brand name, manufactured by BYK)
[Acetylene glycol antifoaming agent]
・ Surfinol DF110D (trade name, HLB value = 3, manufactured by Nissin Chemical Industry Co., Ltd.)
[PH adjuster]
・ Triethanolamine

[Measurement method of average particle diameter]
The average particle diameter was measured in accordance with the trade name “Microtrac UPA” of Nikkiso Co., Ltd.
[Measurement method of Tg]
The Tg was measured using a product name “DSC-6200R” manufactured by SII Nano Technologies, Inc. using a dried emulsion as a sample.

<Preparation of pigment dispersion for ink composition>
Water-soluble resin (methacrylic acid / butyl acrylate / styrene / hydroxyethyl acrylate copolymerized at a mass ratio of 25/50/15/10, weight average molecular weight 12,000) 40 parts by mass, potassium hydroxide 7 parts by mass , 23 parts by mass of water and 30 parts by mass of triethylene glycol mono-n-butyl ether were added and heated at 80 ° C. with stirring to prepare an aqueous resin solution.

  The resin aqueous solution (solid content: 43%) 1.75 kg was mixed with 3.0 kg of coloring material and 10.25 kg of water, respectively, and agitated with a mixing stirrer and premixed to obtain a mixed solution. The above mixed solution was dispersed by a multi-pass method using a horizontal type bead mill equipped with a multi-disc type impeller having an effective volume of 1.5 liters filled with 85% of 0.5 mm zirconia beads. Specifically, two passes were carried out at a discharge rate of 30 liters per hour at a bead peripheral speed of 8 m / sec, and a pigment dispersion mixed liquid having an average particle diameter of 325 nm was obtained. Next, the pigment dispersion mixture was circulated and dispersed using a horizontal annular bead mill having an effective volume of 1.5 liters filled with 95% of 0.05 mm zirconia beads. A screen of 0.015 mm is used, a bead peripheral speed of 10 m / sec, a pigment dispersion mixed liquid volume of 10 kg is dispersed for 4 hours at a circulation rate of 300 liters / hour, a color material solid content of 20%, a water-soluble resin A 5% aqueous pigment dispersion was obtained.

<Preparation of ink composition>
The pigment dispersion prepared above was prepared in such an amount that the colorant would be 2.5% by mass. To this pigment dispersion, each component other than the colorant shown in Table 1 (below) was added so as to have the content (unit: mass%) shown in Table 1, and an inorganic pigment-containing ink composition (Bk, W). ) And an inorganic pigment-free ink composition (C, M, Y). Each ink composition was prepared by putting each component in a container, stirring and mixing with a magnetic stirrer for 2 hours, and filtering through a membrane filter with a pore size of 5 μm to remove foreign matters (impurities) such as dust and coarse particles. . For the water-soluble resin, an amount corresponding to one-fourth of the content of each colorant is added to the ink.

<Cleaning liquid>
The main materials of the cleaning liquid are as follows.
[Cleaning liquid penetrant]
-Acetylene glycol surfactant (trade name Olphine E1010, manufactured by Nissin Chemical Industry Co., Ltd.)
[Humectant]
・ Polyethylene glycol (weight average molecular weight 200)

<Preparation of cleaning solution>
Each component shown in Table 2 (below) was added so as to have the content (unit: mass%) shown in Table 2 to prepare a cleaning solution. The cleaning liquid was prepared by putting each component in a container, stirring and mixing with a magnetic stirrer for 2 hours, and then filtering through a membrane filter having a pore size of 5 μm to remove impurities such as dust and coarse particles.

<Inkjet recording apparatus>
As the ink jet recording apparatus, a printer PX-H10000 (manufactured by Seiko Epson Corporation) modified (hereinafter referred to as “PX-H10000 modified machine”) was used. The modified parts are a nozzle plate, a head, an absorbing member (wiping member), a driving mechanism (wiper unit driving mechanism), and the like.

<Nozzle plate>
A nozzle plate made of single crystal silicon was used. As the nozzle plate, SiC 14 and water vapor were introduced into a chemical vapor deposition (CVD) reactor to form a silicon oxide film (SiO 2 film) formed by the CVD method. The thickness of the SiO2 film was 50 nm. Further, oxygen plasma treatment is performed, and then a chemical vapor deposition method (CVD) is performed using C8F17C2H4SiC13 to form a liquid repellent film (thickness 10 nm) on the SiO2 film, and a silicon nozzle plate with a liquid repellent film is manufactured. did.

  As the absorbent member, a non-woven cupra (density 0.01 g / cm 2, cloth thickness 0.4 mm) was used. A roller having a Shore A hardness of 30 was used as the elastic member. The Shore A hardness is measured by preparing a sheet-like sample by press-molding the outer layer of a foam-molded roller or a thermoplastic elastomer before foam-molding at a temperature of 200 ° C., and the sheet-like sample is subjected to ATSM D-2240. The measurement was performed in accordance with the measurement method specified in 1. In each experimental example, the content of the cleaning liquid was 40% by mass with respect to 100% by mass of the absorbing member.

  The wiper unit driving mechanism presses the absorbing member with a predetermined load from the side opposite to the side contacting the nozzle plate of the recording head with a predetermined load to bring the absorbing member and the recording head into contact with each other. A mechanism for performing a cleaning operation for removing the ink composition adhering to the nozzle plate by the absorbing member by being moved relatively.

<Experimental Examples 1-4>
[Liquid repellent film preservability test]
After recording using the ink composition Bk, C, M, Y, or W shown in Table 1 using a PX-H10000 remodeling machine, a suction operation for sucking ink in the head using a suction pump is performed, and then The cleaning operation (wiping) was performed as shown in Table 3. This cycle was repeated once and repeated 100 times. The cleaning operation was performed along the nozzle arrangement direction in each nozzle row, and the influence on the liquid repellent film for each ink composition was evaluated. That is, the wiping direction is different from the direction of the embodiment in the present invention (the direction shown in FIG. 3C), and the discharge ports of a plurality of nozzles that discharge the inorganic pigment-containing ink composition, and the inorganic pigment-free ink The discharge ports of the plurality of nozzles that discharge the composition were each continuously wiped.

Thereafter, the state of the liquid-repellent film near the nozzle was evaluated with an optical microscope (high precision non-contact level difference measuring instrument “Hismet II” DH2 from Union Optical Co., Ltd.), and the results shown in Table 4 (below) were obtained.
The evaluation criteria were as follows.
A: Level at which liquid-repellent film peeling cannot be observed substantially B: Level at which liquid-repellent film is slightly peeled and discolored, but does not affect ejection C: Liquid-repellent film on the nozzle edge is peeled off, affecting ejection Level D: Level at which the liquid repellent film on the entire surface of the nozzle peels off and the discharge is greatly affected

According to Table 4, the discharge ports of the plurality of nozzles that discharge the inorganic pigment-free ink composition show no damage to the liquid repellent film regardless of the wiping load, speed, and the presence or absence of cleaning liquid on the wiping member. On the other hand, it can be seen that the discharge ports of the plurality of nozzles that discharge the inorganic pigment-containing ink composition have a greater damage to the liquid-repellent film as the wiping load and speed are larger and as the cleaning liquid is not effective.
Based on the above results, it can be confirmed that the inorganic pigment interposed between the wiping member and the nozzle plate surface acts on the nozzle plate surface during wiping and damages the liquid-repellent film. The effect of the invention can be confirmed.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet recording device, 3 ... Carriage, 4 ... Carriage drive mechanism, 5 ... Control board, 6 ... Ink cartridge, 8 ... Platen, 10 ... Recording medium, 20 ... Recording head, 21 ... Nozzle, 22, 22a, 22b, 22c, 22d ... nozzle plate, 24 ... liquid repellent film, 25 ... nozzle plate cover, 26 ... nozzle tip, 30 ... wiper unit, 31 ... wiping member, 32 ... feed roller, 33 ... material removal roller, 34 ... pressure roller 35 ... Case, 50 ... First discharge port array, 51 ... Second discharge port array.

Claims (2)

A first ink composition containing an inorganic pigment;
A second ink composition containing an organic pigment or dye;
On the head face surface having a liquid repellent film formed on the surface, a recording is performed by arranging an ejection port array in which a plurality of ejection ports for ejecting the same ink composition are arranged in the same direction in a direction intersecting the arrangement direction of the ejection ports. An ink jet recording head that is scanned in a direction intersecting the medium;
A wiper unit having a wiping member for wiping the head face surface, a feed roller for feeding out the unused wiping member, and a material removal roller for winding up the used wiping member used for wiping;
A moving mechanism for moving at least one of the wiping member of the wiper unit and the recording head relative to the other;
Control means for controlling the recording head, the wiper unit, and the moving mechanism;
An ink jet recording apparatus comprising:
A first ejection port array for ejecting the first ink composition is disposed on both end sides of the intersecting direction of the ejection port arrays arranged in the intersecting direction, and the second ink composition is disposed on the center side. A second discharge port array for discharging an object,
The control means wipes the discharge port array with the wiping member from a central part of the intersecting direction of the discharge port arrays arranged in the intersecting direction toward one direction of the intersecting direction, and then the wiping member And the recording head, the wiper unit, and the moving mechanism are controlled so that the discharge port array is wiped by the wiping member in the crossing direction from the center to the other direction. Inkjet recording apparatus.   2. The ink jet recording apparatus according to claim 1, wherein the content of the inorganic pigment in the first ink composition is 1.0% by mass or more and 20.0% by mass or less.

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